This invention relates to closed cycle gas turbine systems and, in particular, to such systems operated as high-temperature reactors. Gas turbines are well known for their use in the production of electrical energy, particularly for their use by electric utilities to meet demands for peak power requirements. In general, gas turbines include a compressor which receives atmospheric gases including oxygen and nitrogen and a combustor which receives pressurized gases from the compressor and a hydrocarbon fuel. These constituents are ignited in the combustor and permitted to expand through a turbine. This turbine is typically mounted on the same shaft as the compressor. To avoid confusion herein, this turbine through which the ignited gases expand is referred to as the load turbine or power turbine. Also, as used herein, the term gas turbine refers to the combination of the compressor, the combustor and load turbine. Thus, even through the load turbine is indeed, in one sense, a gas turbine, it is not referred to as such herein so that the term gas turbine may be more appropriately applied to the above-mentioned combination. Furthermore, it should also be noted that several of the more advanced gas turbine configurations employ multiple combustors.
It has relatively recently been recognized that the gas turbine may be used in combination with a steam turbine in a combined cycle plant. These plants, like the gas turbine systems described above, are generally employed in the production of electrical energy. However, the combined cycle plant generally exhibits significantly improved overall operating efficiency because of the fact that the hot exhaust gases from the load turbine are directed through a heat recovery steam generator to produce steam to drive a conventional steam turbine-generator combination. Thus, in conventional combined cycle plants, electrical energy is produced not only from a generator driven by the gas turbine but also by one driven by a steam turbine.
Moreover, in gas turbine systems and in combined cycle systems employing gas turbines, the compressor input is generally open to the atmosphere, thus permitting nitrogen to be introduced into the combustor. Accordingly, as a result of the high temperatures produced in the combustor, it is not unusual that nitrogen oxides are produced. Nonetheless, gases are not generally fed back into the compressor from the load turbine exhaust. However, steam is sometimes introduced into the compressor as a means for limiting the production of nitrogen oxides. Apart from this, gas turbines and combined cycle plants employing gas turbines are generally not used in the production of commercially valuable fluids, chemical elements or compounds.
In a totally unrelated field, it is also known that various fluids and gases may be employed to enhance the recovery of oil from wells from which the primary oil resource has been removed. These fluids include such items as carbon dioxide, steam and nitrogen, all of which may be employed in the tertiary recovery of oil. For example, steam may be produced on site from boilers which are heated, at least in part, from the combustion of previously recovered oil or oil derivatives. Likewise, nitrogen is readily available from atmospheric sources. However, the amount of atmospheric carbon dioxide available is very limited.
It should also be noted that there is significant commercial value to the production of liquefied or solidified carbon dioxide, nitrogen, other air products such as argon and/or steam. Such fluids or solids often find uses in various heating or cooling applications. The growing science of supercritical gas solvents also uses gases such as carbon dioxide and nitrogen.